Many different styles of bags and sacks (hereinafter “bags”) have been formed from sheet material which has been cut, folded and sealed using adhesives. Conventionally, adhesive has been applied to the sheet material by a wheel which receives adhesive from a well and thereafter transfers the adhesive to selected portions of the sheet material as the wheel is rolled over the sheet material. The use of wheels to apply adhesive in this manner slows down production throughput and is generally messy and wasteful of adhesive. To address these issues, hot melt adhesives have been applied by dispensers having slot-type nozzles which dispense thin coats of adhesive to the sheet material as the sheet material is moved passed the nozzle and is brought into contact with the nozzle. While dispensing hot melt adhesives from such slot-type nozzles is generally suitable for bags manufactured from Kraft paper, difficulties have been encountered when hot melt adhesives have been dispensed to polymeric materials from slot-type nozzles. In particular, the increased temperatures of the hot melt adhesive and the slot-type nozzles tend to burn through the polymeric sheet material, or to cause undesirable shrinking and/or wrinkling of the sheet material.
A need therefore exists for improved apparatus and methods for applying adhesives to Kraft paper and polymeric sheet material during the manufacture of bags and which overcomes these and other drawbacks of the prior art.